Recent advances in data communications have given rise to a need for methods of connecting a large number of high performance processors in a distributed processing system. The goal of such methods is to maximize the number of processors that may be simultaneously interconnected and to minimize the time required to make the connections.
U.S. Pat. No. 4,885,739, entitled "Interprocessor Switching Network" and assigned to the present assignee, describes a digital switching network for handling data transfers among a number of processors. The switching network is used with a distributed system of data stations, such as systems of computers or telephones with related supervisory and peripheral equipment. Cluster processors handle messages at each data station and are organized into nodes, each having a node controller. Point-to-point connections are via a switching matrix, and the data transmission uses packet switching techniques to transfer data and various control messages from node to node or within a node.
The switching network described in U.S. Pat. No. 4,885,739 is characterized by several hardware features, including node controllers for handling nodes of cluster processors, gateways for providing an interface for node controllers into the switching matrix, interchange control system, and an interchange that includes the switching matrix. It is also characterized by the use of a multi-level communications protocol, having at least three levels. A first level handles communications between gateways and the switching matrix. A second level handles communications between node controllers. A third level handles communications between application processors of the user's equipment.
U.S. patent application Ser. No. 07/717,420, entitled "Synchronous Node Controllers for Switching Network", assigned to the present assignee, describes a system of node controllers, in which node controller processing is synchronized so that each node controller performs the same tasks simultaneously. This system reduces processing overhead involving the level two and level three protocols.
Typically, in switching networks such as that of U.S. Pat. No. 4,885,739, the level one protocol involves a number of control messages. Processing tasks are triggered by the receipt of appropriate messages. These messages include service, path, and release requests and corresponding acknowledgements. The messages contribute to processing overhead in that not only are a number of different messages used, but also the different messages are exchanged between the various components.
Although this technique works well in practice, as the number of data stations increases, so does the complexity of the switching process. The generation and communication of the various control messages requires increased processing overhead. A need exists for an improved method of using a switching network to handle a large number of messages in a given time.